Device for facilitating the taking of an impression of bone portions of the mouth, and method of using same

ABSTRACT

In order to take the impression of the bony portion of a patient&#39;&#39;s mouth, and then to make an implant-type attachment using that portion of the patient&#39;&#39;s bone structure as a support, a prototype device is used which may readily be shaped to conform to the portion of the bone structure in question and then captivated in impression material such as the material used in conventional fashion, to take the impression of the rest of the patient&#39;&#39;s mouth. The device is removed from the mouth of the patient as a unit with the impression material, after which the attachment is fabricated so that a support portion thereof conforms to the shape of the device. The prototype device comprises a U-shaped flexible sheet which may readily be caused to conform to the shape of the bone structure in question, and a post member extends therefrom into the mouth of the patient, the impression material surrounding and captivating that post member.

United States Patent [191 Linkow [75] Inventor: Leonard I. Linkow, Cedarhurst,

[73] Assignee: Oratronics, Inc., New York, NY.

[22] Filed: Jan. 30, 1973 [21] Appl. No.: 328,123

52 US. (:1. .L 32/17 51 Int. (3|. A61C 9/00 58 Field of Search 32/10 A, 14 A, 2, 19, 17,

-[56] References Cited UNITED STATES PATENTS 4 1 Nov. 4, 1975 Primary Examiner-Russell R. Kinsey Assistant Examiner-J. Q. Lever [57] ABSTRACT In order to take the impression of the bony portion of a patients mouth, and then to make an implant-type attachment using that portion of the patients bone structure as a support, a prototype device is used which may readily be shaped to conform to the portion of the bone structure in question and then captivated in impression material such as the material used in conventional fashion, to take the impression of the rest of the patients mouth. The device is removed from the mouth of the patient as a unit with the impression material, after which the attachment is fabricated so that a support portion thereof conforms to the shape of the device. The prototype device comprises a U-shaped flexible sheet which may readily be caused to conform to the shape of the bone structure in question, and a post member extends therefrom into the mouth of the patient, the impression material surrounding and captivating that post member.

24 Claims, 21 Drawing Figures US. Patent Nov. 4, 1975 Sheet 1 of 4 3,916,527

US. Patent Nov. 4, 1975 Sheet2 of4 3,916,527

US. Patent Nov. 4, 1975 Sheet 4 of4 3,916,527

DEVICE FOR FACILITATING THE TAKING OF AN IMPRESSION OF BONE PORTIONS OF THE MOUTH, AND METHOD OF USING SAME The present invention relates to a prototype device to facilitate the taking of the impression of a portion of the bone structure of a patients mouth, where that bone structure is to constitute a support for an implanttype restoration, and to the method of using that device in order to accurately form the restoration in question.

To replace lost teeth, the dentist or oral surgeon gen erally utilizes one of two basic techniques, depending upon the condition of the remaining natural tooth structure. If there are insufficient natural teeth remaining upon which to construct a fixed bridge, or the remaining teeth are not sturdy enough for this task, the dentist resorts to what is generally described as a removable bridge. In a typical removable denture, a resilient metal clasp is provided which is sprung around the adjacent natural tooth. A major difficulty in the use of such removable bridges is that food particles tend to accumulate in the areas between the removable bridge and the gum, thus requiring the frequent removal of the bridge from the patients mouth to properly cleanse both the bridge and the gum area adjacent thereto. This operation is cumbersome, unpleasant, and somewhat unsanitary.

For these reasons, dentists often prefer to utilize a fixed or permanent bridge. Typically, in a construction of a fixed bridge, the adjacent natural teeth are ground down to form stubs. The superstructure, formed of artificial teeth, includes at either end a crown hollowed out to snugly receive the natural tooth stub, those crowns being cemented permanently over the stubs, thereby permanently securing the entire bridge superstructure in proper position within the edentulous span between these natural tooth stubs.

However, it often occurs that natural teeth do not remain on both sides of the edentulous area. Sometimes there are no teeth at all, at one end or the other. In other instances there are teeth in the forward (anterior) portion of the mouth but no teeth at the rearward (posterior) end of the edentulous span. In other instances where teeth may be present, those teeth may not be sufficiently firmly anchored in the patients mouth as to provide a reliable anchor for the end of the restoration.

Where a full denture is required, either on the upper or lower gum surface, the denture is generally held in place by creating a suction force between the gum surface and the denture. The retention obtained in this manner, however, is somewhat imperfect in that the patient wearing such a denture cannot freely and securely utilize his dentures for biting into hard objects, such as apples, etc., and therefore the patient may, on occasion, place an adhesive on the denture to provide a more secure retention. This procedure is relatively annoying and unpleasant to the denture wearer and is clearly undesireable.

With removable dentures, food particles tend to collect in the regions between the dentures and the gum, forming an unsanitary and unpleasant condition for the denture wearer. Hence, the patient must periodically remove the bridge to provide a proper cleansing of the affected area. This operation is also somewhat cumbersome, unpleasant and unsanitary, and for this reason, a dentist will usually attempt to apply a fixed denture.

Where teeth are not available to support the denture (and it must be supported at both ends) implants are often employed. These are devices which are actually planted in the patients mouth, usually in the bone structure, thereby becoming a more or less permanent part of the mouth structure, and these implants are provided with posts or other projections to which the denture proper can be secured, generally in a permanent manner as through the use of cement. In my US. Pat. No. 3,465,441 of Sept. 9, 1969, entitled Ring Type Implant For Artificial Teeth I have disclosed one type of implanting device designed to be inserted into the bone. In my Patent entitled Template For Implant Denture of Dec. 7, 1971, US. Pat. No. 3,624,904, I disclose another type of implant structure specially designed for use in situations where a large edentulous span must be dealt with.

Bone penetrating implants are excellent in many instances. However, the bone structure of the human mouth, particularly the palatal or upper portion of the mouth, is not very sturdy. Moreover, in many instances the originally present bone structure in the mouth of a given patient becomes resorbed, to a greater or lesser degree, thereby weakening the remaining bone structure to such a degree that it no longer has sufficient body to receive and hold the usual type of bone-penetrating implant device. When resorption occurs the former U-shaped dental arch becomes barely detectable. The palatal vault is frequently so shallow that it and the former dental arch are level. The maxillary sinuses may have enlarged to the point where they have invaded the tuberosities and ballooned toward the former canine eminences. The loss of surface definition has made fitting a conventional denture exceedingly difficult, and the loss of bone has contra-indicated most types of intraosseous implants, that is to say, implants designed to be driven or otherwise positioned in the bone structure itself.

In such situations many attempts have been made to provide other types of support for restorations. One such attempt is to use a pterygoid extension implant. The bone of the pterygoid process lying directly behind the maxillary tuberosity and just distal to the hamular notch is dense basal bone. Such bone provides a distinctly shaped area of strong structure lying within a reasonable continuation of the dental arch.

In the past, to make implants of this type, it was necessary to expose the applicable bone structure and then to use impression material to conform to the shape of the bone structure, after which a model was made from that impression material in conventional fashion and the attachment was then fabricated on the model by the technician. The major problem arising from this new complex implant procedure, admittedly very arduous to execute, is the difficulty in taking an accurate impression of all of the features to be included in the substructure, particularly the pterygoid area and the lateral faces of the maxillary tuberosities. There is not much room for the dentist to maneuver posteriorly because tendons of the tensor veli palatini muscle wrap around the hamulus, and the cheek muscles are often tight.

It is the prime object of the present invention to facilitate taking an impression of the pterygoid area and the lateral faces of the maxillary tuberosities, so that pterygoid extension implants can more readily be designed.

It is a further object of the present invention to provide to the dentist who wishes to supply his patient with 3 a pterygoid extension implant a device which he (the dentist) can use very conveniently, even in the limited space available in the patients mouth and despite the presence of tendons and the tightness of check muscles, to conform to the bone structure desired to be used as a support for one end of a dental restoration.

It is a further object of the present invention to provide to the dentist a device which he can use conveniently to take and hold a given bone conformation and which can then be removed from the patients mouth along with the normal impression material used to take an impression of the patients mouth, the device integrating itself with the impression material so as to be in the proper position to enable the laboratory technician to construct an accurate and precise model of the patients mouth, from which the actual attachment can be designed.

To these ends, the device comprises an essentially U shaped flexible sheet which can be inserted into the patients mouth and shaped around the bone surfaces which are to be used for support. Extending from that flexible sheet via a neck portion is a post member, that post member being oriented relative to the shaped sheet, after the sheet has been shaped around the exposed bone area in question, so as to project into the mouth of the patient. Then when impression material is placed in the patients mouth and an impression taken of the appropriate portion of that mouth, the impression material will surround and captivate the projecting portion of the post member. When the impression material is removed from the mouth the device in question will come out with it, and will retain its shaping corresponding to the bone surfaces in question. The technician can then make from the impression material and the captivated device a model of the patients mouth, including an accurate representation of the shaping of the bone surfaces in question, from which model the attachment proper can be fabricated. That attachment will therefore have at one end a portion which will accurately conform to the bone structure in question and thus will provide a firm anchor for that end of the restoration.

Because the main portion of the device is formed of flexible sheet material it may be inserted into narrow or inaccessible portions of the patients mouth and shaped to the bone structure by means of an inserted thin tool, so that the problems presented by muscle tightness, tendons and the like are greatly minimized. Once the thin sheet material has been shaped to the bone structure, it may be rigidified by coating it with a suitable quick-setting plastic material, the retention of that rigidifying coating to the sheet material being facilitated and intensified by providing the sheet material with perforations distributed over its area into which perforations some of the rigidifying material will penetrate. The sheet material portion of the device may be provided to the dentist in pre-cut pieces of different sizes, or the dentist may be provided with a large sheet of material from which he can cut devices of the desired size and shape. Various embodiments are disclosed, in some of which the post members are formed separately from the sheet material and in some of which the post members are formed integrally with that sheet material.

To the accomplishment of the above, and to such other objects as hereinafter appear, the present invention relates to the structure of a device for facilitating the taking of an impression for a pterygoid extension implant or the like, and to the method of using that de- 4 vice to form such an implant, all as defined in the appended claims and as described in this specification, taken together with the accompanying drawings, in which:

FIG. I is a top exploded view ofa first embodiment of a prototype device of the present invention;

FIG. 2 is a side elevational view thereof;

FIG. 3 illustrates a preliminary shaping step to which the device is to be subjected;

FIG. 4 illustrates the device of FIG. 3 in plan on the bone structure of the patent and being shaped to its final configuration;

FIG. 5 illustrates the rigidification step to which the device is subjected;

FIG. 6 shows the device of FIG. 5 after the post member has been put in position;

FIG. 7 illustrates the device of FIG. 6 after impression material has been placed in the patients mouth;

FIG. 8 illustrates the removal from the patients mouth of the impression material and the prototype as a unit;

FIGS. 9, l0 and 11 are views similar to FIGS. 1, 2 and 3 respectively but of a second embodiment of the prototype device of the present invention;

FIGS. 12, I3 and 14 are views similar to FIGS. 1, 2 and 3 respectively but of a third embodiment of the prototype device of the present invention;

FIG. 15 is a top plan view of a fourth embodiment of the prototype device of the present invention;

FIG. 16 is a bottom plan exploded view of the embodiment of FIG. 15;

FIG. 17 is a side elevational view thereof;

FIG. 18 is a top plan view of one type of packaging and display assembly for a plurality of prototype de vices, such as those in FIG. 1;

FIG. 19 is a side elevational view of the assembly of FIG. 18, illustrating one way in which an individual device may conveniently be removed from the assembly;

FIG. 20 is a top plan view of another way in which a plurality of devices may be provided as a unit; and

FIG. 21 is a side elevational view of the embodiment of FIG. 20.

While the present invention is here specifically disclosed as being used to facilitate the design of a pterygoid extension implant, it will be apparent that it, and the method of using it, have applicability in the formation of implants anchored on bone structure other than the pterygoid process. Any instance where access to bone surface for impression-taking is restricted or difficult represents a potential application where the instant invention may be used. Therefore, use in this specification and in the claims of the term pterygoid extension implant is to be taken as exemplary only, and not limitmg.

It will further be understood that a given restoration will have a number of points of support, preferably at or close to each end and also quite frequently at various points along the length thereof. What is involved here is providing one such point of support, at an end of the attachment. The nature and design of the other points of support for a given attachment will depend upon the particular characteristics of the mouth of the patient in question, and the judgment of the dentist; they may take any of a wide variety of forms, they constitute no part of the present invention, and hence they will not be shown or described here. It will further be understood that the pterygoid extension implant, previously known in the art, constitutes an attachment having a portion which is placed upon the appropriate part of the patients bone structure, after first having exposed that bone by a surgical procedure; after the implant has been put into proper position, the gum is then restored so as to cover the bone-engaging portion of the implant, thereby to assist in retaining it in place. A portion or portions of the implant will extend through the gum to be exposed in the patients mouth, and it is to that portion or portions of the implant (which may take the fonn of protruding posts) that the artificial teeth defining the restoration are ultimately secured, as by cementing. Since all of this is now relatively conventional in dental implant technology, and forms no part of the present invention, it will not be here described.

For general information concerning the pterygoid extension implant and some of the procedures which preceded it in implant technology, reference may be made to my article entitled The Pterygoid Extension Implant at Pages lO-l9 of the Mississippi Dental Association Journal, Volume 28, No. 4, of November, 1972, which is here incorporated by reference.

As we have seen, the nroblem presented to the den- .tist when he desires to iTse a pterygoid extension implant is to gain sufficient access to the bone structure of the pterygoid process, and particularly to the pterygoid hamulus, as to enable him to take an impression thereof. That impression is needed so that the technician can build an accurately shaped model of the patients mouth and then construct or design the attachment on that model. If the model is inaccurate, the attachment will not be properly shaped, and it therefore will not accurately conform to the surfaces which are designed to support it. If there is any clearance or looseness between the attachment structure and the bone structure to support it, the teeth will not be firmly secured in the patients mouth, and if there is any play to the attachment at any given support point, and particularly at the end of the attachment, that play will place excessive stresses on all of the other support points and eventually will very likely lead to the necessity for replacement of the restoration.

The impression device of the present invention comprises a generally U-shaped body portion A formed of flexible sheet material, a neck portion B extending from an intermediate point on the body portion A, and a post member C extending from the neck portion and having an irregular outline so that it can readily be captivated by impression material, most conveniently the material used to form an impression of the more exposed portions of the patients mouth. As disclosed in that embodiment of the present invention illustrated in FIGS. 1-8, the flexible sheet body portion A has a rounded U-shape defining wing portions 16 and 18 and is provided with a plurality of apertures 2 therethrough distributed over its surface, the purpose of which will become apparent hereafter. The material of which the flexible body portion A is formed is not critical, since that body portion A does not form a permanent part of the attachment to be constructed and therefore does not remain in the patients mouth. It must, however, be of material which can be properly sterilized, and which is sufiiciently flexible, while still being substantially .self-sustaining, so that it can be shaped to cause to conform to the bone surfaces desired without excessive effort on the part of the dentist. It should also preferably have a sufficiently low melting point so that it will melt at the temperatures employed in the conventional lost wax process. A soft metal aluminum alloy, provided in sheets having a thickness of perhaps 0.5 mm, is well suited for use in this connection, but the composition and dimensions in question are exemplary only, and are not limiting.

In the embodiment of FIGS. 1-8, the neck portion B is in the form of a tube 4, preferably somewhat flexible, and which therefore may be formed of the same material as the body portion A (although that is not essential), which extends up at right angles to the plane of the body portion A. The inner passage 6 of the tube 4 is designed to receive therein the extending portion 8 of the post member C, that post member C having at the upper end thereof a portion 10 of irregular outline, preferably defined by outwardly extending cross-pieces 12. In the embodiment here under discussion the post member C is separate from the body portion A and the neck portion B, and may be provided in a size (length) large enough to be used with all mouths. When that is done lines of weakening 14 may be provided at spaced intervals along the length of the portion A, so that the post member C may be cut down to size, as will become apparent hereafter.

When the device of FIGS. 1 and 2 is to be used the wings 16 and 18 of the body portion A, those being the length of that body portion to one side and the other of the neck portion B, are bent so that their bottom surfaces face one another, and the tube 4 defining the neck portion B is bent so as to extend substantially at Next the thus-shaped device is inserted into the patients mouth after the pterygoid process has been exposed by a surgical procedure, so that, in the specific embodiment illustrated in FIG. 4, the wings l6 and 18 are received around the maxillary tuberosity 20, with the connecting body portion from which the neck portion B extends being received in the hamulus notch area 22 between the maxillary tuberosity 20 and the pterygoid hamulus 24, the bent neck portion B thus extending down from the bone structure in the upper portion of the patients mouth, as shown in FIG. 4. The dentist will then, by inserting a suitable tool 26, and by pressing with that tool 26 on the wings 16 and 18, cause those wings 16 and 18 accurately to conform to the shape of the outer surfaces of the maxillary tuberosity 20. If those bone surfaces present any problem insofar as causing the wings 16 and 18 to be conformed thereto or, after they are thus conformed, inhibiting removal of the body portion A from the bone structure to which it has been conformed, the bone structure itself may be remodelled before the wings l6 and 18 are caused to conform thereto, but usually this will not be necessary.

Next, as shown in FIG. 5, the wing portions 16 and 18 of the device of the present invention are rigidified, so that they will reliably retain the bone-confonning shape that they have now assumed. This can readily be accomplished by applying to the exposed surfaces of the wings 16 and 18 a rigidifying coating, for example, by brushing onto those surfaces a coating 27 of a quicksetting plastic material such as acrylic resin. This is done while the wings 16 and 18 are in position on the bone surface, as by brushing the plastic on with a brush 28. The rigidifying coating should, of course, reliably adhere to the wings l6 and 18, and it is for that reason that the perforations 2 are provided in those wings. When the acrylic or other rigidifying coating is applied portions of that coating will penetrate the perforations 2, thus ensuring proper retention of the coating on the right angles to the wings 16 and 18, as is shown in FIG. 30 3 7 wings.

Thereafter, as may be seen in FIG. 6, the post member C is inserted into the inner passage 6 of the neck portion 4, after first being .cut down to size, as by being severed along one of the weakening lines 14, so that after insertion into the neck portion B, the cross-pieces 12 comprising the irregular outline portion 10 of the post memberC will extend down into the mouth of the patient to the occlusal plane. While in some instances frictional forces between the post member C and the neck portion B might be sufficient to retain the two assembled together, it is generally preferred that the post member C, after being inserted into the neck portion B, be cemented in place.

Next, as illustrated in FIG. 7, an impression is taken of the patients mouth, and the impression material 30 will surround the irregular outline portion 10 of the post member C as that portion extends to the occlusal plane. The impression material 30 most conveniently is integral with the impression material used, in conventional fashion, to make an impression of the remainder of the patients mouth. After the impression material has set it is removed from the patients mouth, again as is conventional. In accordance with the present invention, as the impression material 30 is removed from the patients mouth it will carry along with it the device of the present invention. Since the irregular outline portion 10 of the post member C is completely surrounded by the impression material 30 it will be captivated thereby, and as the impression material 30, when it is removed from the patients mouth, pulls the post member C along with it, the shaped and rigidified body portion A and the neck portion B will come out of the patients mouth as well, the wings l6 and 18 retaining their shape corresponding to that of the bone surfaces where support is to be sought with the impression material 30 preferably contacting the lower edges of the wing portions 16 and 18.

The combination of the impression material 30 and the device of the present invention, constituting a unit as it is removed from the patients mouth, is then employed to make an accurate model of that mouth. The conventional portion of the impression material 30 constitutes a negative of the mouth portions that it comes in contact with, those mouth portions producing an appropriately shaped concavity in the body of impression material while the space between the Wings 16 and 18 constitutes a reproduction of the bone structure where the attachment is to be supported. Thereafter, a model is made from the impression material and the prototype device wings l6 and 18, and on that model the technician will devise and fabricate the attachment atructure to be implanted, as by means of the conventional lost wax process.

Because the thin soft metal wings 16 and 18 are used conform to and to remember every detail of the )utline of the desired surface portions of the maxillary :uberosity 20, it is no longer necessary to use conven- :ional impression materials to try to get an accurate imression of the pterygoid process and the buccal and nalatal surfaces of the tuberosity; the wings 16 and 18 just that, and require very little space to do it.

In the embodiment of FIGS 1-8 the post member C is eparate from the body member A and neck portion B. n the embodiment of FIGS. 9-11 the post member C md neck portion B are made in one piece and are pernanently secured to the body portion A. With this arangement, it is the irregular outline portion 10' of the post member C which must be elongated, thus calling for a larger number of cross-pieces 12' than in the embodiment of FIG. 2. When the post member C is cut to proper length in the embodiment of FIGS. 9-11 it is the extreme end portions of the irregular outline portion 10 which are severed therefrom. Thus, as may be seen from comparing FIG. 10 with FIG. 11, the post member C in its original form may be provided with three sets of cross-pieces 12', but for a particular mouth it may be cut down so that only two sets of such cross-pieces are provided. In the embodiment of FIGS 9-11 it is preferred that the post member C itself be somewhat flexible, whereas in the embodiment of FIGS. l-6 the post member C could be rigid.

In the embodiment of FIGS. 12-14 the post member C and the neck portion B are not only integral with the body portion A but are formed in the same plane as the body portion A and from the same sheet material. In this embodiment, as in the embodiment of FIGS. 9-11, the post member C must be made sufficiently long, and with a sufficient number of cross pieces 12 or other elements providing an irregular outline, to fit all mouths, the post member C then being cut down to size by severing the desired length from the free end thereof.

In the embodiment of FIGS. 15-17 the body portion A and neck portion B are formed integral with one another, from the same piece of flexible sheet material and normally extending in the same plane with one another, but the post member C, as in the embodiment of FIGS. 1-6, is formed separate from the remainder of the device. The neck portion B is defined by a section of the flexible sheet material which is bent around, as at 32, to define the tube 4'. The post member C may be the same as that which was described in connection with the embodiment of FIGS. l-6.

The devices of the present invention may be provided to the dentist in many different fashions. As illustrated in FIGS. 18-19, pre-cut devices may be provided in various sizes, as by being adhered to a backing or display sheet 34, which sheet can be peeled away from the device of desired size in order to make that device available to the dentist, as shown at the right hand side of FIG. 19. Alternatively, the individual devices could be packaged in the manner shown in FIG. 18 but they could all be of a single size, which the dentist could easily shape with a scissors to the desired size and/or contour to correspond to the problems presented by a particular patients mouth. Alternatively, as shown in FIGS. 20-21, the dentist could be provided with a single unitary sheet 36 of flexible perforated material with neck members B in place, from which he could cut the body portions A (and other portions if appropriate) of the device that he wishes to use. As is shown in FIGS. 20 and 21 template outlines 38 may be provided on the sheet as a guide. The packaging and display embodiments of FIGS. 18-21 are, it will be recognized, with respect to the specific embodiment of FIGS. l-6. It will be readily apparent that the same packaging and display principles could be applied to the other disclosed embodiments as well.

Through the use of the impression facilitating device of the present invention, the taking of impressions of bone surfaces desired for use in supporting a dental restoration is greatly facilitated, particularly where those bone surfaces (such as those of the maxillary tuberosity) are in inaccessible portions of the mouth where other anatomical features prevent ready access. Hence in difficult restoration problems, particularly where bone resorption has taken place so that conventional bone implants cannot be used, a means has been provided, which will at the least make the taking of an impression of a requisite bone areas much less troublesome to the dentist and much less of an unpleasant experience to the patient, and in some instances may even make possible what has heretofore as a practical matter not been possible.

While but a limited number of embodiments of the present invention are here specifically disclosed, it will be apparent that many variations may be made therein, all within the scope of the present invention, as defined by the following claims.

I claim:

1. A device for facilitating the taking of an impression for a pterygoid extension implant comprising (A) an essentially U-shaped flexible sheet with a tubular neck portion extending from an intermediate point thereon remote from both ends thereof, (B) a post member extending from said neck portion and having an irregular outline, said post member comprising a separate piece insertable into said neck portion, and

,(C) a body of impression material set within said neck portion and about said inserted post member end integrating said sheet and said post member, whereby said sheet may be shaped to provide a first surface conforming to the bone structure of a patient and a body of impression material set on a second surface of said sheet and around said post member will capture the latter, thereby to integrate said device with said body of impression material.

2. The device of claim 1, in which said neck portion extends substantially at right angles to the plane of said sheet.

3. The device of claim 1, in which said neck portion extends substantially parallel to the plane of said sheet.

4. A device for facilitating the taking of an impression for a pterygoid extension implant comprising an essentially U-shaped flexible sheet with a neck portion extending from an intermediate point thereon remote from both ends thereof and with a post member extending from said neck portion comprising a longitudinal part and, at the end thereof, a plurality of cross-pieces, thereby to define an irregular outline, whereby said sheet may be shaped to provide a first surface conforming to the bone structure of a patient and a body of impression material set on a second surface of said sheet and around said post member will capture the latter, thereby to integrate said device with said body of im pression material.

5. The device of claim 4, in which said neck portion is tubular and said post member comprises a separate piece insertable into said tubular neck portion.

6. The device of claim 5, in which said neck portion extends substantially at right angles to the plane of said sheet.

7. The device of claim 5, in which said neck portion extends substantially parallel to the plane of said sheet.

8. The device of claim 4, in which said post member is integral with said neck portion.

9. The device of claim 4, in which said neck portion and said post member comprise integral sheet material extensions of said flexible sheet.

10. The method of making a pterygoid extension implant which comprises providing a device comprising .an essentially U-shaped flexible sheet with a neck portion extending from an intermediate point thereon remote from both ends thereof and with a post member extending from said neck portion and having an'irregular outline, shaping said sheet about a desired portion of the maxillary tuberosity and ptyergoid process of a patient, positioning said post member relative to said sheet so that the irregular outline thereof extends to the occlusal plane of the patients mouth, taking an impression of the desired portion of the patients mouth and causing the impression material to captivate the irregular outline portion of said post member, removing the impression material and said device, as a unit, from the patients mouth, and using said unit to form an attachment a part of which will have the same shape as said sheet.

11. The method of claim 10, in which said neck portion is tubular and said post member comprises a separate piece insertable into said tubular neck portion.

12. The method of claim 10, in which said neck portion extends substantially at right angles to the plane of said sheet.

13. The method of claim 10, in which said neck portion extends substantially parallel to the plane of said sheet.

14. The method of claim 10, in which said post member is integral with said neck portion.

15. The method of claim 10, in which said post member comprises a longitudinal part and, at the end thereof, a plurality of cross-pieces, thereby to define said irregular outline.

16. The method of claim 10, in which said neck portion and said post member comprise integral sheet material extensions of said sheet.

17. The method of claim 10, in which said sheet is perforated, whereby stiffening material applied to said sheet will penetrate said perforations and become firmly adhered to said sheet.

18. The method of claim 11, including the step, after said sheet has been shaped about a desired portion of the maxillary tuberosity and pterygoid process of a patient, and before the impression of the desired portion of the patients mouth is taken, of coating said sheet with a stiffening material, thereby to rigidify said sheet.

19. The method of claim 12, including the step, after the flexible sheet has been shaped about a desired portion of the maxillary tuberosity and pterygoid process of a patient, and before the impression of the desired portion of the patients mouth is taken, of coating said flexible sheet with a stiffening material, thereby to rigidify said sheet.

20. The method of claim 13, including the step, after the flexible sheet has been shaped about a desired portion of the maxillary tuberosity and pterygoid process of a patient, and before the impression of the desired portion of the patients mouth is taken, of coating said flexible sheet with a stiffening material, thereby to rigidify said sheet.

21. The method of claim 14, including the step, after the flexible sheet has been shaped about a desired portion of the maxillary tuberosity and pterygoid process of a patient, and before the impression of the desired portion of the patients mouth is taken, of coating said flexible sheet with a stiffening material, thereby to rigidify said sheet.

22. The method of claim 15, including the step. after the flexible sheet has been shaped about a desired portion of the maxillary tuberosity and pterygoid process of a patient, and before the impression of the desired portion of the patients mouth is taken, of coating said flexible sheet with a sitffening material, thereby to ri- 24. The method of claim 17, including the step, after said sheet has been shaped about a desired portion of the maxillary tuberosity and pterygoid process of a patient, and before the impression of the desired portion of the patients mouth is taken, of coating said sheet with a stiffening material, thereby to rigidify said sheet. 

1. A device for facilitating the taking of an impression for a pterygoid extension implant comprising (A) an essentially Ushaped flexible sheet with a tubular neck portion extending from an intermediate point thereon remote from both ends thereof, (B) a post member extending from said neck portion and having an irregular outline, said post member comprising a separate piece insertable into said neck portion, and (C) a body of impression material set within said neck portion and about said inserted post member end integrating said sheet and said post member, whereby said sheet may be shaped to provide a first surface conforming to the bone structure of a patient and a body of impression material set on a second surface of said sheet and around said post member will capture the latter, thereby to integrate said device with said body of impression material.
 2. The device of claim 1, in which said neck portion extends substantially at right angles to the plane of said sheet.
 3. The device of claim 1, in which said neck portion extends substantially parallel to the plane of said sheet.
 4. A device for facilitating the taking of an impression for a pterygoid extension implant comprising aN essentially U-shaped flexible sheet with a neck portion extending from an intermediate point thereon remote from both ends thereof and with a post member extending from said neck portion comprising a longitudinal part and, at the end thereof, a plurality of cross-pieces, thereby to define an irregular outline, whereby said sheet may be shaped to provide a first surface conforming to the bone structure of a patient and a body of impression material set on a second surface of said sheet and around said post member will capture the latter, thereby to integrate said device with said body of impression material.
 5. The device of claim 4, in which said neck portion is tubular and said post member comprises a separate piece insertable into said tubular neck portion.
 6. The device of claim 5, in which said neck portion extends substantially at right angles to the plane of said sheet.
 7. The device of claim 5, in which said neck portion extends substantially parallel to the plane of said sheet.
 8. The device of claim 4, in which said post member is integral with said neck portion.
 9. The device of claim 4, in which said neck portion and said post member comprise integral sheet material extensions of said flexible sheet.
 10. The method of making a pterygoid extension implant which comprises providing a device comprising an essentially U-shaped flexible sheet with a neck portion extending from an intermediate point thereon remote from both ends thereof and with a post member extending from said neck portion and having an irregular outline, shaping said sheet about a desired portion of the maxillary tuberosity and ptyergoid process of a patient, positioning said post member relative to said sheet so that the irregular outline thereof extends to the occlusal plane of the patient''s mouth, taking an impression of the desired portion of the patient''s mouth and causing the impression material to captivate the irregular outline portion of said post member, removing the impression material and said device, as a unit, from the patient''s mouth, and using said unit to form an attachment a part of which will have the same shape as said sheet.
 11. The method of claim 10, in which said neck portion is tubular and said post member comprises a separate piece insertable into said tubular neck portion.
 12. The method of claim 10, in which said neck portion extends substantially at right angles to the plane of said sheet.
 13. The method of claim 10, in which said neck portion extends substantially parallel to the plane of said sheet.
 14. The method of claim 10, in which said post member is integral with said neck portion.
 15. The method of claim 10, in which said post member comprises a longitudinal part and, at the end thereof, a plurality of cross-pieces, thereby to define said irregular outline.
 16. The method of claim 10, in which said neck portion and said post member comprise integral sheet material extensions of said sheet.
 17. The method of claim 10, in which said sheet is perforated, whereby stiffening material applied to said sheet will penetrate said perforations and become firmly adhered to said sheet.
 18. The method of claim 11, including the step, after said sheet has been shaped about a desired portion of the maxillary tuberosity and pterygoid process of a patient, and before the impression of the desired portion of the patient''s mouth is taken, of coating said sheet with a stiffening material, thereby to rigidify said sheet.
 19. The method of claim 12, including the step, after the flexible sheet has been shaped about a desired portion of the maxillary tuberosity and pterygoid process of a patient, and before the impression of the desired portion of the patient''s mouth is taken, of coating said flexible sheet with a stiffening material, thereby to rigidify said sheet.
 20. The method of claim 13, including the step, after the flexible sheet has been shaped about a desired portion of the maxillary tuberosity and pterygoiD process of a patient, and before the impression of the desired portion of the patient''s mouth is taken, of coating said flexible sheet with a stiffening material, thereby to rigidify said sheet.
 21. The method of claim 14, including the step, after the flexible sheet has been shaped about a desired portion of the maxillary tuberosity and pterygoid process of a patient, and before the impression of the desired portion of the patient''s mouth is taken, of coating said flexible sheet with a stiffening material, thereby to rigidify said sheet.
 22. The method of claim 15, including the step, after the flexible sheet has been shaped about a desired portion of the maxillary tuberosity and pterygoid process of a patient, and before the impression of the desired portion of the patient''s mouth is taken, of coating said flexible sheet with a sitffening material, thereby to rigidify said sheet.
 23. The method of claim 16, including the step, after said sheet has been shaped about a desired portion of the maxillary tuberosity and pterygoid process of a patient, and before the impression of the desired portion of the patient''s mouth is taken, of coating said sheet with a stiffening material, thereby to rigidify said sheet.
 24. The method of claim 17, including the step, after said sheet has been shaped about a desired portion of the maxillary tuberosity and pterygoid process of a patient, and before the impression of the desired portion of the patient''s mouth is taken, of coating said sheet with a stiffening material, thereby to rigidify said sheet. 